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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

14953 results found.

  1. GRB 200310A: MAXI/GSC detection
  2. GRB 200306C: Swift/UVOT Detection
  3. GRB 200308A: Fermi GBM Final Real-time Localization
  4. GRB 200306C: Calar Alto 2.2m upper limit
  5. GRB 200307A: Fermi GBM Final Real-time Localization
  6. GRB 200306A: AstroSat CZTI detection
  7. GRB 200306C: KCT upper limit of the optical afterglow
  8. GRB 200306B: Fermi GBM Final Localization Correction
  9. GRB 200306C: OSN 1.5m afterglow detection
  10. GRB 200306C: GOTO upper limits
  11. GRB 200306C: BOOTES-1 detection of the optical afterglow
  12. GRB 200306C: FRAM-ORM afterglow detection
  13. GRB 200306C: Swift detection of a burst with an optical counterpart
  14. Swift GRB200306.95: Global MASTER-Net OT detection
  15. Swift GRB200306.95: Global MASTER-Net OT detection
  16. GRB 200306B: Fermi GBM Final Real-time Localization
  17. GRB 200306A: Potential LCO Optical Afterglow Detection
  18. GRB 200306A: Swift detection of a burst
  19. Konus-Wind observation of GRB200303A
  20. GRB200210A AstroSat observations
  21. LIGO/Virgo S200302c: Upper limits from Insight-HXMT/HE observations
  22. GRB 200219A: AstroSat CZTI detection
  23. GRB 200303A: GOTO observations upper limit
  24. GRB 200228A: AstroSat CZTI detection
  25. GRB 200303A: CALET Gamma-Ray Burst Monitor detection
  26. GRB 200219C: VLA Detection
  27. GRB 200303A: Swift detection of a burst
  28. GRB 200303A: Fermi GBM Final Real-time Localization
  29. LIGO/Virgo S200224ca: No counterpart candidates in TOROS observations
  30. LIGO/Virgo S200302c: no counterpart candidates in the Swift/BAT observations
  31. LIGO/Virgo S200302c: No counterpart candidates in HAWC observations
  32. LIGO/Virgo S200302c: Upper limits from Fermi-GBM Observations
  33. GRB 200228B: Liverpool Telescope imaging
  34. GRB 200228C: Insight-HXMT/HE detection
  35. GRB 200228A: Swift/BAT detection and arcminute localization from GUANO
  36. LIGO/Virgo S200213t: No significant EM counterparts identified from continued GECKO observation of host galaxy candidates
  37. GRB 200227A: Mondy optical upper limit
  38. GRB 200228B: Swift detection of a burst
  39. GRB 200228B: Fermi GBM Final Real-time Localization
  40. GRB 200227A: Insight-HXMT/HE detection
  41. IceCube-200227A : Upper limits from Insight-HXMT/HE observations
  42. GRB 200228A: Fermi GBM Final Real-time Localization
  43. HAWC-200216A: No Neutrino Counterpart in ANTARES Search
  44. IceCube-200227A: IceCube observation of a high-energy neutrino candidate event
  45. GRB 200227A: Swift detection of a burst
  46. GRB 200227A: Fermi GBM Final Real-time Localization
  47. Konus-Wind observation of GRB 200219C
  48. LIGO/Virgo S200224ca: DESGW Optical counterpart candidates from DECam
  49. Konus-Wind observation of GRB 200219A
  50. GRB 200224A: Calar Alto 2.2m optical afterglow detection
  51. LIGO/Virgo S200225q: Upper limits from Insight-HXMT/HE observations
  52. LIGO/Virgo S200224ca: Upper limits from Insight-HXMT/HE observations
  53. LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
  54. IPN triangulation of GRB 200221A (short)
  55. LIGO/Virgo S200225q: Upper limits from Fermi-GBM Observations
  56. LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
  57. LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
  58. GRB 200224A: Swift/UVOT Detection
  59. GRB 200224C: Fermi GBM Final Real-time Localization
  60. GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
  61. GRB 200224B: Fermi GBM Final Real-time Localization
  62. GRB 200224A: Swift detection of a burst
  63. GRB 200223A: Fermi GBM Final Real-time Localization
  64. IPN triangulation of GRB 200219B (inconsistent with the LIGO/Virgo S200219ac)
  65. GRB 200219C: CALET Gamma-Ray Burst Monitor detection
  66. GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
  67. GRB 200221A: Fermi GBM Final Real-time Localization
  68. GRB 200219C: Swift-XRT afterglow detection
  69. GRB 200219C: Fermi GBM detection
  70. LIGO/Virgo S200213t: AT2020clw/ZTF20aanaoyz, AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes 10.4m GTC spectroscopy
  71. GRB 200219C: Fermi-LAT detection
  72. GRB 200219C: Fermi GBM Final Real-time Localization
  73. LIGO/Virgo S200219ac: Fermi GBM transient event not confidently associated with GW signal
  74. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  75. GRB 200219B: Fermi GBM Final Real-time Localization
  76. GRB 200219A: Swift detection of a short burst
  77. GRB 200219A: Fermi GBM Final Real-time Localization
  78. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  79. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  80. LIGO/Virgo S200213t: APO Upper Limits for ZTF20aanakes/AT2020cly
  81. Further Swift-XRT observations of Swift J0840.7-3516
  82. GRB 200215A: CALET Gamma-Ray Burst Monitor detection
  83. GRB 200216A: Fermi GBM detection
  84. GRB 200216A: Swift/BAT detection and arcminute localization from GUANO
  85. GRB 200216B: Swift detection of a burst
  86. GRB 200216B: Fermi GBM Final Real-time Localization
  87. GRB 200216A: Fermi GBM Final Real-time Localization
  88. LIGO/Virgo S200213t: CLU/NED Galaxies in the 4-Update Localization Volume
  89. GRB 200215A: Fermi GBM detection
  90. GRB 200215A: Swift detection of a burst
  91. GRB 200215A: Fermi GBM Final Real-time Localization
  92. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  93. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  94. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  95. LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
  96. LIGO/Virgo S200213t: No Counterparts from GECKO observation of host galaxy candidates in GW-neutrino detection overlap area
  97. LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
  98. LIGO/Virgo S200213t: AT2020ciy/ZTF20aamvqxl, AT2020cjg/ZTF20aamvoxx and AT2020cje/ZTF20aamvtip 10.4m GTC spectroscopy
  99. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  100. GRB 2002011A: AstroSat CZTI detection

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